Variable flow restriction device



June 25, 1963 s. s. SMITH VARIABLE FLOW RESTRICTION DEVICE Filed Dec. 8, 1961 IIlfl 5 a 0 1 Z n z 1 A 5,5, a 1 E 5 v /M W 3 M I I 7 W M w WW I I g Q5 M flm V41 l a WW A a Z z I 8 u g 1 z m m, 4 M a a 4 10 I 3 Wm WEE. M Z V a 1 g i 4 Z 0 7 4 H//'/// l M w z Emu a k ,0 1 4, ME a $74! j I a m a United States Patent 0.

3,095,006 VARIABLE FLOW RESTRICTION DEVICE .Sydney S. Smith, Scarsdale, N.Y., assignor to Smith Development (10., Pebble Beach, Calif., a corporatien of California Filed Dec. 8, 1961, Ser. No. 158,095 9 Claims. (Cl. 137-2695) This invention relates to a fluid variable flow restriction device.

A primary purpose of the invention is to provide a variable flow restriction device which permits generally unregulated flow in one direction, and a smaller, regulated flow in the opposite direction.

:Another purpose is a variable flow restriction device which can be adapted for numerous fluid measuring and for throttling operations.

Another purpose is a device of the type described which provides precisely controlled fluid flow in one direction. Other purposes will appear in the ensuing specification,

drawings and claims.

cylinder 12 having end flanges 14 and 16. One end of the body may be closed by a cap 18 having a flange 24) which is secured to the flange 16 by suitable threaded bolts or the like 22. The other end of the body may have .a cover 24 having an annular flange 26 which is secured to the flange 14- by suitable threaded bolts or the like 23.

An O-ring 3-0 may seal the flanges 26 and 14 and an O-ring 32 may seal the flanges 16 and 20.

Mounted within the body 19 is a plug 34 having an axial generally central flow passage 36 which extends completely through the plug. Suitably attached to the upper end of the plug is a shaft or the like 33 which has a flow passage 40 in communication with the passage 36 and opening into a chamber 4-2 formed within the cover member 24 and above the plug. The shaft 33 may be fixed vary the restricted flow passage hereinafter described. The shaft 355 passes through a sleeve 44, which may be integral with the cover 24, and has a suitablehand wheel or the like 46 fixed at its upper end. An O-ring 48 may seal the upper end of the shaft 38 and the sleeve 44.

Fixed along one side of the sleeve 44 and attached to the hand wheel 46 is a suitable indicator 50 which may be calibrated in any desired manner to indicate the volume of fluid flowing through the restrictive flow passage hereinafter described.

A port 52 in the cover 24 may function either as an inlet port or an outlet port, depending upon the direction of flow, and is in communication with the chamber 42 and hence the flow passage 36. The cap 18 has a port 54 which also may be either an inlet port or an outlet port and which is in communication with the lower end of the flow passage 36 through a check valve hereinafter described.

At the lower end of the flow passage 36 is an enlarged chamber 56, the lower end of the chamber being closed by a plug 58 which has a passage 60 generally the same in cross section as the passage 36. The plug 58 may be suitably screwed into the bottom of the plug 34. The opposite ends of the chamber 56 have valve seats 62 and 64 which are adapted to seat a ball valve 66. A coil spring or the like 68 biases the valve element 66 against Varied by moving the to the plug and is adapted to rotate the plug to thereby either of the seats depending upon which side of the valve element the spring is located. As can be seen from the drawing, when the valve is in the position shown, fluid can flow from the port 54 through the passage 36 and out port 52. There will be no flow from port 52 down through passage 36 and out port 54-. However, by reversing the relative positions of the spring 68 and the valve element 66 there can be substantially unrestricted flow in the opposite direction. The plug 58 is removable in order that the direction of unrestricted flow can be reversed.

The outer surface of the plug 34 may have a suitable thread 76, which is preferably a square thread. In like manner, the inner surface of the cylinder 12 has a square thread '72. Both the plug and the cylinder 12 are tapered and the threads 70 and '72 are generally identical. In this way when the plug is in the completely closed position, as in FIGURE 1, the threads will be completely in mesh. On the other hand, when the plug 34 is not completely within the body 10 there will be space between the crest of the thread 72 and the root of the thread 70 and between the crest of the thread 70 and the root of the thread 72. These two spaces are indicated at 74 and 76. The spaces 74 and '76 are isolated one from the other because the sides of the threads 70 and 72 fit tightly together. The spaces 74 and 76 define a pair of generally parallel helical flow passages that run from the chamber 42 down .to the port 54. The flow passages are annular and uniformly extend in an axial direction. The cross sectional area of the flow passages or spaces 74 and 76 may be plug relative to the body 10. As the plug is moved deeper into the body the spaces 74 and '76 will decrease in size and the flow of fluid will be more restricted. As the plug 34 is moved upward of the body 10 the size of the spaces 74 and 76 will be increased and the flow of fluid will similarlybe increased. The flow passages 74 and 76 have a uniform cross section throughout as the threads 71 and 72 are uniform. When the plug 34 is in the completely closed position, an O-ring 73 will form a seal between the plug and the cap 18. The flow passages 74 and 76 are arranged to control the flow of fluid in either direction and it is only the size of the passages that restricts and controls the flow of fluid.

The use, operation and function of the invention are as follows:

The restrictive flow device shown is effective to precisely regulate the flow of fluid in one direction through a pair of parallel and annular flow passages which extend in a helical manner from an inlet port toward an outlet port. The size of the flow passages and hencethe volume of flow can be precisely controlled by moving the plug 34 either into or out of the body 10. At low pressures the flow through the passages 74 and 76 will be generally laminar whereas at high pressures there will be a turbulent flow. Any type of liquid or gas which has a flow characteristic that can be regulated can be passed through the flow restriction device shown with excellent results.

Preferably the threads on the plug and cylinder 12 are square. What is essential is that the threads define an annular flow passage. As shown herein, with square threads there are two annular flow passages. Other thread formations may be satisfactory if they provide for control of the cross sectional area of the flow passage. For example, the conventional screw thread having inclined side surfaces would not be satisfactory, as the thread would either completely stop the flow or would let a substantially unregulated amount of fluid flow axially through the space between the threads.

The invention has particular application in an arrangement where substantially unrestricted flow is desired in one direction and a limited amount of restricted and controlled flow is desired in the other direction. For

example, considering the form of the invention shown in the drawings, substantially unregulated flow will be permitted from port 54 past the valve element 66, through passage 36, into the chamber 42 and then out port 52. The only flow in the opposite direction would be that permitted by the flow passages 74 and '76. As mentioned above, the valve element 66- may be reversed so that the unrestricted flow is in the opposite direction.

The invention has numerous applications as a throttling device to control the flow of fluid in one direction. The device may also be used as a flow meter, without a check valve and central passage, if the pressure drop across the device is known. The device as shown in the drawings has particular application in pipelines, in which it controls the flow from fuel racks on diesel engines which are operating centrifugal pumps. The device shown may also control valves which throttle pump stations on pipelines or the like.

The device shown and described is a particularly accurate flow meter or flow restriction device because of the long flow conduit. A long conduit of small size is much more reliable and accurate than a short restriction.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that 'there are many modifications, substitutions and alterations thereto within the scope of the following claims.

I claim:

1. A fluid variable flow restriction device including an outer generally cylindrical body and a generally cylindrical plug within the body, said body having an inlet and an outlet axially spaced therefrom, the outer surface of the plug and the inner surface of the body having mated surfaces that define a pair of parallel generally helical restricted annular flow paths, each generally uniform in cross section, said flow paths being in communication with said inlet and being directed uniformly and in an annular direction toward the outlet, movement of said plug relative to said body being effective to change the cross sectional area of said flow paths.

2. The structure of claim 1 further characterized by an axial flow path from the inlet to the outlet substantially larger in cross sectional area than either of said generally helical flow paths, and check valve means in said axial flow path permitting flow in only one direction.

3. A fluid variable flow restriction device including an outer generally cylindrical body and a generally cylindri cal plug within the body, said body having an inlet and an outlet axially spaced therefrom, the outer surface of the plug and the inner surface of the body being tapered and each having mated threaded areas, the space between the threads defining two separate and parallel generally helical flow paths in communication with the inlet and outlet and extending uniformly in an axial direction, movement of said plug relative to said body being effective to vary the cross sectional area of said flow paths.

4. The structure of claim 3 further characterized by an axial flow passage in said plug from the inlet to the outlet, said axial flow passage being substantially larger in cross sectional area than either of said helical flow passages, and check valve means in said axial flow passage permitted flow in only one direction.

5. The structure of claim 3 further characterized in that the threads on said plug and body are generally square in cross section, with the two flow passages being at the crest and root of the threads.

6. A fluid variable flow restriction device including an outer generally cylindrical body and a generally cylindrical plug the body, said body having an inlet and an outlet axially spaced therefrom, vthe outer surface of the plug and the inner surface of the body being tapered and each having mated square-threaded areas which define two separate and generally parallel helical flow paths from the inlet to the outlet, one path being at the root of the threads and the other being at the crest, relative movement between said plug and body being effective to vary the cross sectional area of said flow paths with said paths being completely shut off when the plug is completely received within the body, an axial flow pasage in said plug connecting the inlet to the outlet and check valve means in said axial flow passage effective to permit flow in only one direction.

7. The structure of claim 6 further characterized by an enlarged chamber in said axial flow passage, a valve member in said chamber, and means normally biasing said valve member against one end of said chamber to thereby block fiow in one direction.

8. The structure of claim 7 further characterized by a valve seat at each end of said chamber and surrounding the entrances of said axial flow pasage into said chamber, and means permitting reversal of positions of said valve member and biasing means wherebysaid valve member will close said passage at one or the other selected end of said valve chamber.

9. The structure of claim 7 further characterized in that the means normally biasing said valve member includes a coil spring positioned in said chamber.

References Cited in the file of this patent FOREIGN PATENTS Great Britain Feb. 8, 1934 484,369

Great Britain May 4, 1938 

1. A FLUID VARIABLE FLOW RESTRICTION DEVICE INCLUDING AN OUTER GENERALLY CYLINDRICAL BODY AND A GENERALLY CYLINDRICAL PLUG WITHIN THE BODY, SAID BODY HAVING AN INLET AND AN OUTLET AXIALLY SPACED THEREFROM, THE OUTER SURFACE OF THE PLUG AND THE INNER SURFACE OF THE BODY HAVING MATED SURFACES THAT DEFINE A PAIR OF PARALLEL GENERALLY HELICAL RESTRICTED ANNULAR FLOW PATHS, EACH GENERALLY UNIFORM IN CROSS SECTION, SAID FLOW PATHS BEING IN COMMUNICATION WITH SAID INLET AND BEING DIRECTED UNIFORMLY AND IN AN ANNULAR DIRECTION TOWARD THE OUTLET, MOVEMENT OF SAID PLUG RELATIVE TO SAID BODY BEING EFFECTIVE TO CHANGE THE CROSS SECTIONAL AREA OF SAID FLOW PATHS. 